Briton Jenson Button will miss next week's first Formula One tests since the end of the season after suffering two hairline cracks to his ribs while go-karting, his Honda team said on Friday.
A team statement said Button, who took the first Grand Prix win of his career in Hungary last August, had hurt himself during a karting test as part of his winter preparations.
He will skip the three-day Barcelona tests starting on Tuesday to ensure the condition is not aggravated.
Button was returning to Britain from Japan on Friday after attending a Honda 'Thank You Day' at the Motegi circuit where he met some of the 26,000 customers invited to celebrate Honda's motorsport successes.
The Barcelona tests are the first with all teams running on Bridgestone tyres following the departure of Michelin at the end of the season that finished in Brazil last month.
Brazilian Rubens Barrichello and newly-appointed test drivers Christian Klien of Austria and Briton James Rossiter will test for Honda.